Lapping machine



H. S. INDGE LAPPING MAcHiNE Feb. 6, 1945.

2 Sheets-Sheet 1 y 'Filed March '7, 1944 HEBREW? *3- IHDf-v Feb. 6, 1945.

- LAPPING MACHINE Filed MalICh 7, 1944 2 sheets-s116761', 2

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invention;

Patented Feb. 6,1945

` LAPPING MACHINE Herbert' S. Indge, Westboro, Mass., assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts4 Application March "l, 1944, Serial No. 525,381

. s claims. (ci. 51-118) This invention relates to lapping machines,v and v I more particularlyto a lapping machine for simultaneously lapping the opposed faces of' a wor-k piece. One object of the invention is, to make a thoroughly practical lapping machine for .simultaneously lapping the opposed faces' of a plurality of workpieces. Another object of the invention is to provide alapping machine having two op posed lapping elements and work holders which are relatively `rotated and 'revolved between said lapping elements for simultaneously lapping. the

' opposed faces on a plurality of relatively thin work pieces.

- vA further object of the Ainvention is to provide a lapping machine having a pair of opposed lapping wheels vand a plurality of work cages or holders therebetween which are rotated and revolved during a lapping operation with a mechanism for imparting a relative reciprcatory motion between the cages 'and the cage driving mechanism. Other objects will be in part obvious or in part pointed out hereinafter.

The -invention` accordingly consists in the -features of eonstruction, combinations vof 'ele-- ments, and arrangements of parts, as will vbe exemplified inthe structure to be hereinafter described and the scope of the application of whic .will be indicated in the following claims.

In the accompanying drawings, in which is Ashown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a-vertical-sectional view through the lapping elements land the workholder and cage driving and reciprocating mechanism; l

Fig. 2 isa fragmentary'side elevation, on a.re duced scale, of a lapping machine embodying this Fig. 3 is a fragmentary plan view, on a 'reduced scale, takenA approximately on the line 3 3 of Fig, 1, with the upper lap removed;

In the preferred. construction the upper lapping wheel I2 is supported by a lfloating 4 connection at the lower end of a vertically movable spindle I3. The spindleV I3 is slidably supported within a frame I4 whichois formed integral with'an vertical column I6 which is in turn fixed. rela. tive to the base ill. The. arm I5 is arrangedso f rthat it may be adjusted vertically on thcolumn clamped I6'.by means of a locating collar I1 which is the column I Baby means of a clamparm I5. The arm I5'.is adjustably supported on va ing bolt I8. The arm I5 is preferably arranged so that'it may be swung to an inoperative position toffacilitate" loading of `work holders and work pieces in the machine.

As shown in Fig. 2, the lower portion ofthe arm I5 is provided with a slot I9. A studY 20 is ilxedly mounted on 'the collar I1 and serves to limit the syvingingmovement of the arm I5 and Fig. 4 is a fragmentary sectional view, taken approximately on the Aline 4-4 of Fig. 1, shoviing the gear train for driving the fluid pump and also the cage driving mechanism; Fig. 5 is a fragmentary sectional view, on an enlarged scalejshowing the floating 'connection between the upper lap and vits supporting spindie; and I Fig. 6 is a fragmentary /sectional view, taken approximately on the line 6-6 of Fig. 5.

A 'lapping machine has been illustrated in the drawings, comprising a base I0 which serves as a support for a pair of opposed lapping wheels II and I2 having opposed plane lapping faces.

the upper. lapping wheel I2. The spindle I3 is provided with a rack 2| whichsmeshes with a ro- .tatable pinion (not shown).' The lapping wheel I2 and its supporting spindle I3 may. be raised or lowered by means of a spoked manually oper.-

able wheel 22 vwhich 4is flxedly connected to the` pinion (not shown). The hand wheel 22 and the pinion (not shown) are both fixedly meunted on a rotatable shaft 23. The shaft 23 is also provided 'with a ratchet wheel 24, and a ratchet pawl 25 is pivotally mounted on the arm I5 so that the'upper lapping wheel I2 may be readily raised to an inoperativeposition and held in this position by meacns of the'pawl 25 and the ratchet wheel 24. The construction above described is standard and well known and has been used in l lapping, machines for -many years. For` further details of this construction, reference may be had vto the expired U. S. patent to H. S. Indge. No.

1,610,527, dated 'December 14, 1926.

The upper lapping wheel I2 is-provided with ae-.floating connection so that the lapping wheel I2 may readily align itself with the work pieces` carried by the work holders to be hereinafter descril'red.. The lower end of the spindle I3 is pro-- vided with a .partial spherical surface 26 which is formed integral withireduced portion 21 of the spindle I3. The spherical surface 26 is ar` ranged to slide 'within av cylindrical aperture 28 formed in a spider 29 which supports the uppery lapping wheel I2. The lower end ofthe reduced portion 21- of the spindle I3 is provided with a thrust collar 30 which is flxedly mounted there- 0n by means .of a nut 3L A .clearance is provided between the lower surface of the spider 29 and the "thrust collar 30 which serves to facilitate a free aligning movement of the upper lapping wheel I2 and its supporting spider 29 rela.

goingv disclosure that the upper lapping wheel* I2 is free to oat relative to its supporting spin? dle so that. its lapping surface may align itself with the upper faces of the work pieces to be lapped. -f

The lower lapping wheel 'Il is Supported on a spider 48"which is xedly mounted on the upper v end of a vertically arranged cylindrical sleeve 4|.

The sleeve 4| is slidably supported in a bearing surface 42 formed in a housing 43 which is fixedly mounted on the base I0. The sleeve 4| is arranged so that it may be reciprocated in an axial direction by means of a reciprocating mechanism to be hereinafter described.

The lapping machine is provide/dwith a plurality of work holders 45, 46, 41 ,andf 48, each of whichis provided with a plurality of work receiv- .ing apertures 49.` This machine is particularly adapted for lapping work pieces of relatively` thin cross .section and the work holders 45 are, therefore, relatively thin disks, being in some cases vonly a few thousandths'of an inch in thickness.

These work cages may be formed of a resincid material, vsuch as Micarta. The periphery of the work holders 45, 46 and 41 is formed as a gear by means of which a combined rotary and revolving movement may be imparted to the work holders and work pieces while in an operating position between the lapping wheels I I and I 2.

In 4order to impart a rotary. and revolving movement to the work holders 45, 46, 41 and l48, a central gear 58 is fixedly mounted on the upper end of a rotatable shaft 5l. 'Ihe gear 58 is arranged to mesh with the gear teeth formed on the work cages. A ring gear 52 having internal gear teeth formed thereon is arranged concentric gear 52 comprising a gear 63 which is vfixedly mounted on a hub formed integral with the worm gear 62. The gear 63 meshes with an idler gear 6 4 (Fig. 4) which is rotatably mounted on a supporting stud 65. The idler gear 64 meshes with a gear 65 which is keyed to a rotatable shaft 61.

The shaft 61 is rotatably journalled in anti-friction bearings 68 and 69 both of which are supported by the housing 43. The upper end of the shaft 61 is provided with a gear 10 which meshes with an internal ring gear 1I which is fixedly mounted on a downwardly extending portion of the' spider 53. It will be readily apparent from the foregoing disclosure that a' rotary .motion of the shaft 50 will be imparted through the worm 6I, theworm gear 62, the gear 63, the idler gear 64, the gear 66, the shaft 61, the gear 10, and the internal ring gear 1I to in'ipart a rotary motion to the spider 53 and the ring gear 52. The

driving mechanism above described may be r' ranged to. rotate the gear 50 and the ring gear gear 52 and the gear 50 due` to continuous rotat-v ing and revolving movements of the work holders,

itis desirable to impart a relative reciprocating movement between the work. holders and the driving gears and 52 so that the wear on the driving gears is distributed over substantiallythe entire area of the gear teeth. In the preferred construction.. this reciprocatory motion. is obtained by imparting a reciprocatory motion to the lower lapping wheel in a manner to be hereinafter described. The reciprocating mechanism Y preferably comprises a hydraulically operated 1 mechanism including a fluid pump I5y which is ported on the lower end of theshaft 61. The

pump plunger or piston 19 is fixedly supported with the gear 58 and the lapping wheels I'I and also by bearings 56 and 51.which are lcarried by the sleeve 4I.

A driving mechanism-is provided for imparting a relative rotary motion to the gear 50 and the ring gear 52 which comprises a shaft 60 which is .journalled in suitable bearings (not shown) in like section of the base I0 so that oil or other' the base I8. The shaft 68 may be driven either by a belt driving mechanism, such as shown in the expired patent to Indge above referred to, or

maybe motor driven, as desired. A worm 6I is fixedly mounted on the shaft 68 and is arranged to mesh with a worm gear 62 which is keyed to the lower end of the. shaft 5I. It will bereadily vapparent from the foregoing disclosure that a rotary motion ,of the shaft 60 will be imparted through the worm vISI and :the worm gear. 62 toY rotatelthe shaft 5I and the gear 58. ,-A' driving mechanism is provided for the vririg on a collar 88 which is in turn supported on a bushing 8| which is fixedly mounted relative toA the gear 63 and worm gear 62. It -will be readily.

apparent from the vferegoing disclosure that when the shaft 5I is-rotated by the driving mechanism above described, it will impart a rotary motion to the eccentric 18 which in turn imparts a reciprocatory motion to the pump housing 16.'

A fluid reservoir 82 is provided within a boxoperating fluid may be contained therein to a sufficient level so that the entire pump housing 16 is immersed within the huid. Fluid is pumped from the reservoir 82 through an intake port 83 and passes around a bail check valve 84,y due to action of the pump cylinder 15 reciprocating relative-to its piston 19. Fluid 'from' a pump chamber 85 is forcedthrough a ball check valve 86, exible pipe 81, to a control valve 88.

In the position of the valve 88 shown in Fig. 1

uid from the pipe* 81 passes through a port 89 into va valve chamber and passes through a central aperture 9| in the valve 88 into a cylinder chamber 92 formed Within the` housing 43. When fluid under .pressure is admitted into the cylinder chamber 92, the lower end of the sleeve 4I and the bearing bushing 51- serves as a piston-to raise the spider 48 and the lower lapping wheel II and the work holders 45, 46, 41 and 48. The upward movement of the lapping wheel II is'transmitted through the work pieces to raise the upper lapping wheel I2 so that both wheels aremaintain'ed in operativelapping contact with the work pieces during the reciprocatory movement. A pressure on a stud 95, the stud 95 being fixed relative to the base I of the machine. The downwardly extending portion of the bell crank lever ridesin a groove96 formed in the right-hand end of the valve 88. A Ihorizontally extending portion of the bellcrank lever 94 is provided with a rounded end 91 which rides in a clearance slot 98 formed in the lower end'of a connecting link or rod 99. 'I'he rod 99 is xedly connected by 'a stud |00 with the sleeve 4|.

A load and fire mechanism is provided comprising an arrow-pointed projection |0I f ormed integral with the'bell crank lever 94 which coacts with av spring-pressed arrow-pointed plunger |02 which is supported in the housing 43. The load and re mechanisml above described serves quickly to shift the valvef88 into a reverse positionv after the upper lapping wheel I2 and lower lapupward stroke of the parts.

engages the rounded end 91 ofthe bell crank lever to rock the bell crank lever in a counterclockwlse direction. Movement of the lever 94 in a clockwise direction serves to shift the valve 88 into the position illustrated in Fig. 1 to again initiate an I have shown four work holders 45, 46, 41 and l 48 in operative position in Fig. 3. It should be ping WheelII have been raised to the desired 4f position.V

When the valve 88 isv shifted toward the left to lcut off the passage of fluid under pressurev into the cylinder chamber, 92, a port |03- is opened so that the weight of the upper lapping wheel I2 and the lower lapping Wheel |I together with its supl gears, an adjustable throttle valve |04 may be provided, by means of which the exhaust-of fluid from the cylinder chamber 92 may be readily controlled so that the rate of downward motion may be regulated and controlled. l It will be readily apparent that the upward movementof the lapping wheels II and I2 relative to the cage driving gears -50 and 52 isa slow intermittent motion caused bya small shot of oil -being forced from the pump chamber 85 into-the cylinder 92 each time the eccentric 18 causes a reciprocatory stroke of the pump housing 16.

In the position of the parts shown in Fig. 1, the upward movement of the lapping wheels and I2 will continueI intermittently until the lower face of the slot 98 engages the rounded end 91 of the bell crank lever 94 and rocks the bell crank lever 94 in a clockwise direction so as to shift the valve 88 toward the left (Fig. 2). The movement of the valve 88 is controlled at first by the upward movement of the sleeve 4| until the arrow point |0| passes by the high point of the direction `so as to intermittently causev a ver-4 III) spring-pressed arrow point |02,after which the released compression of the arrow point |02 rapidly shifts the valve 88 through its remaining stroke toward theleft to cut ofl fluid under pressure passing through the port 89, and to open the port I 03 so that a downward stroke of the lapping wheels may be initiated. The downward'movement of the lapping-wheels andV I2 together with the work holders 45, 48, 41 and 48 continues until the upper end of the elongated slot' 98 .gear 52.

understood that any number of work holders may be used. that is, two, three, four or flve,which can be symmetrically positioned with their gear teeth meshing with the center lgear and the ring The operation of this improved lapping machine will be readily apparent from the foregoing disclosure. I2 is raised by turningthe spoked, manually opand the arm I5 may then be swung about-the column |.6 so that the work holders may be rea\'.lily. loaded into the machine. The geared work holders 45,A 46, 41 Vand 48 are then inserted so that they mesh with both the center gear 50 and the rirrg gear 52. The work pieces to be lapped are then inserted in the apertures 49 formed in the work holders. Thev upper lap I2 may thenv be swung into an operative position and lowered by releasing the pawl 25 andvma'nually turning the spoked wheel 22 to lower the upper lapping wheel |2 into operative engagement. with the upper surfaces of the work piece to be lapped. The machinemay then. be started and the shaft rotated simultaneously to impart a relative rotary motion to the gear 50v and thel ring gear 52 so as to impart a combinedl rotary and revolving movement to the work holders 45, 46, 41 and 49. This movement carries'the work pieces to be lapped through anirregular path between the opposed faces of the lapping wheels II tand I2 During this lapping operation, a relative axial reciprocatory motion vis imparted between the work. holders 45, 46, 41 and 48 and the work holder driving the gears 50I and 52 oy means of theuid pressure operated mechanism above described. As the eccentric 18 is rotated by the gear 6,6, a reciprocatory motion is imparted to thepump housing 16- which serves to draw fluid from the-reservoir-82 .through the-port 83' and ball check valve 84 into thegpump chamber 85 during the movement of the pump-housing in the pump housing in one direction, and to force uid from the pump chamber 85 through the ball vcheck valve 85 into the cylinder` chamber 92 when the pump housing is moved in the opposite tical motion of the sleeve 4| to raise the lower lap |l together with the workholders 45, 45, 41. and 48 supported thereby relative to the certergear 50 and the vring gear 5I. This upward movement of the work holders continues until the bell crank lever 94 actuated by the upward movement of the sleeve 4| shifts the valve 88 so as to cut offfadmission of fluid under prestsure to the chamber 92.

, through the passage 9|. through the port |08 and the throttle valve |04, into the reservoir 82. The

weight of the spindle 4| and thelapping wheel I I v serves to force iluid from the chamber 92. By

In a loading position, the upper lap of downward movement of the work holders 45,

46, 41 and 48 may be readily controlled. The

downward movement of the parts continues until the bell crank lever 94 is again rocked into the position shown in Fig. 1 so as again to admit uid under pressure to the chamber 92 to initiate an upward movement of the parts. It`will thus be seen that during the lapping operation,

a continuous reciprocating motion is imparted to cause a relative reciprocatingl motion between the Work holders and the gears for driving the same so as to distribute the wear between the successfully achieved. As many possible embodiexternally geared work holdersl between said ments may be made of the above invention and Jas many changes might be made in the embodiment'above set forth, it is tobe understoodthat al1 matter hereinbefore set forth or shown' in the ,accompanying drawings -is tovbe interpreted as illustrative and not in a limiting sense.

I claim:

l. In a lapping machine havinga pair of op- 4. In a lapping machine having a pair of opu* .posed lapping wheels, a gear at the center of said wheels, a ring gear concentric with said pinion gear andsurrounding said wheels,"a plurality of externally geared work holders between said wheels which mesh vwith said pinion gear and said ring gear, each of said work holders having a. plurality of work receiving apertures, means relav tively to rotate said pinion gear and said ring gearto impart a combined rotating and revolving movement'to said work holders, and means including a fluid pressure piston and cylinder to impart a relative axial movement between said 'work holders and said work holderI driving gears.

5. Ina lapping machine a pair of opposed lapping wheels, a gear at the center of said wheels, a ring gear concentric withsaid pinion gear and surrounding said wheels, a plurality of externally posed lapping wheels, a plurality of externally geared work holders'between said wheels, a work 'holder driving mechanism including a center gear yandy a ring gear each of which mesh with teeth on said holdersmeans relatively to rotate said gears to v,impart a-combined rotating and revolving movement to said'holders,l and means to impart a relative axial reciprocation between said work holders and said work holder driving gears during a lapping operation.'

2. In a lapping machine having a pair'of opposed-lapping wheels, a gear at the center o`f said wheels, a gear concentric with said pinion gear and vsurrounding said wheels, a plurality of vexternal geared work holders betweensaid wheels which mesh with said pinion gear and said ring gear, means relatively' to rotate said pinion gear and ring gear to'impart a combined rotating and A revolving movement to said work holders, and

.ment to said work liolders relative to said work holder driving gears. A. l

.6. In a lapping machine havingga pair of opposed lapping wheels, an axially movablel spindle Yto support one of said lapping wheels, a plurality of work holders between said wheels,- a work holder means to impart a relative axial reciprocation n wheels lwhich mesh With said pinion gear and said lring gear, each of said Work holders having 'a plurality of work receiving apertures, means relatively torotate said pinion- 'gear and said ring gear to impart a combined rotating and revolving movementto said work holders, and means to impart aV relative axial-reciprocation between said l -holders and saidpinion and ring gears duringa lapping operation -so as to distribute the wear therebetween.

driving mechanism including a center gear and a ring gear each of which mesh with g'ear teeth formed on said work holders, means relatively to rotate said gear and ring gear to impart ai 'combined rotary vand' revolving movement to said work holders, and means axially to reciprocate said spindle and the lower lapping wheel so as to impart a reciprocatory movement to said work holders relative to the work holder drive gears.

7. In a lapping machine as claimed in eclaim 6, the combination with the parts and features therein specified, of a'fluid pressure operated reciprocating mechanism for said spindle including a piston and cylinder, the end of said spindle l the combination with the parts and features.

i therein speciied, 'of'. a iluid pressure operated spindle reciprocating mechanismincluding a piston' and cylinder, said spindle serving as a piston, a self-contained uid pressure system including a I iluid pump which is actuated by said work holder driving mechanism, andmeans including a valve which is actuatedby axial movement of said spinwork holder driving gears.

" dle to control the admission to and exhaust of uid from said cylinder so as to impart a reciprocatory movement 'to'. said work holders. relative to the HERBER'r's. mDGE. 

